Takahashi, A.Matsuoka, Y.Onoue, M.Strauss, M. A.Kashikawa, N.Toba, Y.Iwasawa, KazushiImanishi, M.Akiyama, M.Kawaguchi, T.Noboriguchi, A.Lee, C.-H.2025-01-302025-01-3020240004-637Xhttps://hdl.handle.net/2445/218258We report the distribution of black hole (BH) masses and Eddingont ratios estimated for a sample of 131 low luminosity quasars in the early cosmic epoch (5.6 < z < 7.0). Our work is based on the Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs) project, which has constructed a low luminosity quasar sample down to M1450 ∼ − 21 mag, exploiting the survey data of Hyper Suprime-Cam installed on Subaru Telescope. The discovery spectra of these quasars are limited to the rest-frame wavelengths of ∼1200–1400 Å, which contain no emission lines that can be used as BH mass estimators. In order to overcome this problem, we made use of low-z counterpart spectra from the Sloan Digital Sky Survey, which are spectrally matched to the high-z spectra in overlapping wavelengths. We then combined the C iv emission line widths of the counterparts with the continuum luminosity from the SHELLQs data to estimate BH masses. The resulting BH mass distribution has a range of ∼107–10M⊙, with most of the quasars having BH masses ∼108M⊙ with sub-Eddington accretion. The present study provides not only a new insight into normal quasars in the reionization epoch, but also a new promising way to estimate BH masses of high-z quasars without near-infrared spectroscopy.1 p.application/pdfeng(c) American Astronomical Society, 2024Forats negres (Astronomia)GalàxiesQuàsarsBlack holes (Astronomy)GalaxiesQuasarsinfo:eu-repo/semantics/article7538052025-01-30info:eu-repo/semantics/openAccess